CODEWITHSUNDEEP
c++g++include-path
jww
jww

Reputation: 102296

Instruct compiler to ignore header prefix found in a #include

[As Cornstalks explained below, I'm trying to strip a header prefix that's used in an #include. So it appears this question is not a duplicate of How to make g++ search for header files in a specific directory?]

I'm making some changes to a library. I have the library locally, so its not installed in its customary system location.

I have a test source file and its sided-by-side with the library. The test file has a bunch of includes like:

#include <foo/libfoo.h>

And it also has a bunch of customary includes, like:

#include <iostream>

I'm trying to compile the test file using:

$ g++ ecies-test.c++ -I. -o ecies-test.exe ./libcryptopp.a

And (the space between -iquote . does not appear to make a difference):

$ g++ ecies-test.c++ -I. -iquote . -o ecies-test.exe ./libcryptopp.a

The problem I am having is I don't know how to tell g++ that <foo/libfoo.h> means "./libfoo.h". Effectively, I'm trying to strip the prefix used to include the header. I've looked in the manual under 2.3 Search Path, but it does not really discuss this scenario.

I have about 60 extra test files I use for the library. And each has 10 or 20 includes like this. So I can't go through and change #include <foo/libfoo.h> to #include "./libfoo.h" in 500 or 600 places.

I tried @rici's work around by creating the fictitious directory structure, but it broke GDB debugging. GDB cannot find symbols for class members, so I can't set breakpoints to debug the code I am attempting to modify.

How do I tell the compiler to look in PWD for system includes?

Below is a typical error. ECIES_FIPS is in my local copy of the library.

$ g++ -DNDEBUG=1 -g3 -Os -Wall -Wextra -I. -iquote . ecies-test.c++ -o ecies-test.exe ./libcryptopp.a
ecies-test.c++:29:17: error: no member named 'ECIES_FIPS' in namespace
      'CryptoPP'
using CryptoPP::ECIES_FIPS;
      ~~~~~~~~~~^
ecies-test.c++:44:5: error: use of undeclared identifier 'ECIES_FIPS'
    ECIES_FIPS<ECP>::Decryptor decryptor(prng, ASN1::secp256r1());
    ^
ecies-test.c++:44:16: error: 'ECP' does not refer to a value
    ECIES_FIPS<ECP>::Decryptor decryptor(prng, ASN1::secp256r1());
               ^
/usr/local/include/cryptopp/ecp.h:30:20: note: declared here
class CRYPTOPP_DLL ECP : public AbstractGroup<ECPPoint>
    ...

In case it matters:

$ g++ --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn)
Target: x86_64-apple-darwin12.6.0
Thread model: posix

Upvotes: 0

Views: 1944

Answers (3)

Avi Ginsburg
Avi Ginsburg

Reputation: 10596

I have about 60 extra test files I use for the library. And each has 10 or 20 includes like this. So I can't go through and change #include to #include "./libfoo.h" in 500 or 600 places.

If the above criteria is just a matter of convenience, then a tool like sed can be used to do all the work. Something like

$ sed -i 's/\(^\s*#include\s*[<"]\)foo\/\([^>"]*[>"]\s*$\)/\1\2\t\/\/ This line was replaced/' *

will replace all the occurrences of #include <foo/file.h> with #include <file.h> (you might have to adjust it slightly, I'm on a Windows machine at the moment and can't test it). This will work if all the files are in the PWD. If there is a more complex file structure, then it can be used in conjunction with grep and xargs.

NOTE: Make sure that the svn directories are ignored when using.

Upvotes: 1

rici
rici

Reputation: 241761

There is no option which tells gcc to ignore directory prefixes in include paths. If your program contains #include <foo/header.h>, there must be some path_prefix in the include list such that path_prefix/foo/header.h resolves to the desired file.

While you cannot configure gcc to ignore the foo, you can certainly modify the filesystem as you please. All you need is that there be somewhere a directory foo which maps onto the directory where the header files are stored. Then you can add the parent of that directory to the search path.

For example:

mkdir /tmp/fake
ln -s /path/to/directory/containing/header /tmp/fake/foo
gcc -I /tmp/fake ...             # Ta-daa!

Upvotes: 4

Corb3nik
Corb3nik

Reputation: 1177

Using the -I option to add the current folder as an include directory, you could create a folder called "foo" in the current directory and put your libfoo.h file inside.

Obviously, this doesn't strip the "foo" prefix in your #include, but it is a workaround.

Upvotes: 1

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